JACKIE NORTHAM, BYLINE: I'm Jackie Northam in Washington. Today at the U.N., Russia and China vetoed a Western-backed draft resolution that warned of sanctions against the Syrian regime unless it complies with a peace plan.

This is the third time those two countries have used their veto power to block a resolution on Syria. Britain's U.N. ambassador, Mark Lyall Grant, called the decision by Russia and China appalling, and said it would lead to further bloodshed in Syria.

MARK LYALL GRANT: By exercising their veto today, Russia and China are failing in their responsibilities as permanent members of the Security Council, to help resolve the crisis in Syria. They are failing the people of Syria. The effect of their actions is to protect a brutal regime.

NORTHAM: Russia, a longtime ally of Syria, and China have consistently opposed sanctions against the Assad regime, saying all parties in Syria are responsible for the violence. Speaking through an interpreter, Russia's envoy, Vitaly Churkin, called the draft resolution biased.

VITALY CHURKIN: The Western members of the council spoke today with unacceptable statements. They could have done something - anything - to promote dialogue between the Syrian parties; to prevent the further militarization of the Syrian crisis, rather to fan the flames of extremists, including terrorist groups.

NORTHAM: The draft resolution included a provision to renew the mandate of the U.N. monitoring mission in Syria. The military monitors were deployed last April. with the task of overseeing the implementation of the peace plan authored by special envoy Kofi Annan. But they have been in lockdown for more than a month because of the increasing violence in Syria. After today's vote, Britain said it would draft a new resolution, extending the mission for another 30 days. But a spokesman for President Obama said the U.S. does not support extending the mission.